1. Field of the Invention
The present invention relates to the field of key management schemes, and more particularly, the present invention relates to a key management scheme for Internet working protocols to provide additional security at the network layer.
2. Art Background
The Internet comprises a spiderweb of connected networks which criss-cross the globe and permit users to send and receive data packets between computers. Although many of the computers coupled to the Internet are disposed at fixed locations, portable computer systems may be physically moved from one location on a network to another. Wireless links coupling the computers to the Internet, including direct satellite links, also allow users to access the Internet from remote areas. As a result of the dramatic increase in the use of the Internet throughout the world, concerns regarding network security naturally arise.
A variety of schemes have been proposed to increase security on the Internet, and a number of these schemes have been adopted. For example, encryption and authentication procedures known as Privacy Enhanced Mail (PEM) provide for enhanced privacy in electronic mail ("e-mail") services over the Internet. Additionally, schemes for utilizing PEM for secure remote user authentication have also been proposed. (See, for example, copending U.S. patent application Ser. No. 253,802, filed Jun. 3, 1994, entitled "Method and Apparatus for Secure Remote User Authentication in a Public Network", assigned to the Assignee of this patent application, Sun Microsystems, Inc., and hereby incorporated fully by reference.)
However, even if a remote user has been authenticated, there still exists the possibility that an intruder (herein referred to as a "cracker") may mount an active attack to interject himself in data transfers across the Internet. Although a user may incorporate a scheme for secure remote user authentication prior to login, a cracker may sever one of the authenticated parties from the Internet connection, and receive and transmit substitute data packets to the other unwitting party (or potentially to both parties). Once the Internet connection is established, data packets are sent over the network in the clear. For example, a cracker may interject himself between, for example, a user "A" in communication with a user "B" on the Internet, and issue a disconnect command to user A. Upon receipt of the disconnect command from the cracker, user A believes that user B has severed the connection. The cracker may then take over the communication established with user B, such that user B does not know that user A is not sending him data packets. Thus, a number of security issues exist when sending data over the Internet, including a cracker's ability to monitor data packets in the clear and to interject himself in the communication line such that he may receive and send data packets to unwitting users. It is, therefore, advantageous to put authenticity and privacy features at the network layer on the Internet. However, the majority of the privacy and authentication protocols which have been proposed provide session oriented key management schemes. Unfortunately, many of the commonly used network layer protocols (for example IP) are session-less datagram oriented protocols.
The present invention provides a key management scheme that is particularly well suited for use in conjunction with session-less datagram protocols such as the Internet protocols, and the proposed replacement candidates known as Connectionless Network Layer Protocol ("CLNP") and Simple Internet Protocol Polymodal ("SIPP"). As will be described, the present invention's key management scheme prevents crackers from monitoring the transfer of data in the clear over the Internet by encrypting every data packet.